No, its the way you are built,
Its the luck of the draw, Race, religeon, physical build have nothing to do with it,
One thing I say, Tiny pussies are for fucking, Big pussies are for down town to lunch.

Generally speaking no he would not be able to tell unless there was a huge difference between them.

For the sake of argument let's say 6 inches is average. I am a little more then a few incehs shorter then average and the width is proportionately as small. My wife started sleeping with a guy that above average, take how much I was short of average, double it and add it to average (yes rediculously huge) and significantly thicker then what would be propotional.

Yes in such a situation a man can feel the change in "tightness" if she is with the other guy enough to start changing to accomidate him regularly.